1. Field of the Invention
The present invention relates to the production of sailing vessels with effective sail disposition and with mechanisms for manipulating and releasing the sail from the driving position.
2. Brief Description of the Background of the Invention Including Prior Art
In principle, the same driving forces act on a sail of a boat as are acting on a vertically disposed aircraft wing. The thrust distribution at the sail is composed of the overpressure on the windward side and of the underpressure on the leeside and is determined by the physical laws of buoyancy forces for aerodynamic buoyancy, that is in case of a subsonic advancing flow the resulting thrust forces on the suction side and on the pressure side are in a relationship of about two to one.
In order to improve the conditions of the employment of sails the following requirements are considered to achieve optimal action by a sail based on experiences and rules observed in the past.
The advance flow speed on the backside of the sail should be increased in order to increase the underpressure to a maximum value based on particular technical provisions.
Further, the ratio of the height of the sail to the area of the sail should be favored with respect to the height of the sail as far as possible in order to achieve a high effectiveness, since the buoyancy of a wing profile is basically determined by the aspect ratio (=span width squared divided by the wing area). The requirement of an optimum wing extension or in other words of an optimum height of the sail has naturally set limits given by technical and construction considerations, since an extremely high sail would represent a correspondingly strong heeling torque for the hull of a boat. These requirements are not or only insufficiently met by conventional sailing vessel constructions, for example in case of a far extending foresail (Genova), in order to feed the advancing wind to the rear of the main sail. Or, in case of larger vessels several foresails are employed, this however is associated with additional rope work and therefore does not permit rapid sailing maneuvers and in addition creates a tendency of the boat to move to the windward side and is restricted to larger boats due to the space requirements. In addition, new constructions based on using a stronger thrust via the sail rear face by providing slots in the sails have not become commonplace due to the relatively poor guiding of the air flow on the rear face of the sail and the poor efficiency while sailing before the wind according to this method, since the efficiency is decreased corresponding to the necessary pressure loss on the windward side caused by the slots. In addition, the attempt to dispose sail flaps behind the slots in order to achieve a kind of nozzle effect failed to be a breakthrough, since this solution is associated with the following disadvantages:
1. This solution employs only part of the circulation on the windward side of the sail face. PA1 2. The optimum uniform flow course on the upper side or on the leeside of the profile is disturbed by vortex formation at the flaps. PA1 3. If the flaps are employed only on one side, then they are effective only with regard to certain directions of wind and vessel. PA1 4. If the flaps are employed on both sides, then the flow course of the windward side profile is additionally disturbed by the fluttering flaps and the problem of vortex formation as set forth above under 2 is of increased importance.
A related state of the art is described in the U.S. Pat. No. 689,648 (Lowry). Lowry teaches slotted sails in such a way as to result in individual profiles which overlap each other in part in the longitudinal direction of the boat, where this holds both for the main sail as well as for the head sail. The use of this sail is effective as long as the wind remains constant, that is, a wind where the flow direction and the flow speed do not change relative to the boat or, respectively, its sails. In addition, the direction of the boat or ship has to be maintained constant.
If the direction of the ship is no longer constant and this becomes extreme upon a turning of the boat, that is, upon a change in direction, then the flow direction changes to the other side of the boat. The windward and the leeward directions are exchanged and the individual profiles have to be stretched or, respectively, varied via the foot rope corresponding in each case. This is performed in a conventional way, that is, via in each case individual steering ropes which are coordinated to the individual segments of the sail and which thus can only be operated individually and are correspondingly attached at a corresponding large number of points. In case of a required change in the sail, that is, in case of one of the maneuvers recited above, each steering line has to be individually released, the individual profile has to be individually steered and/or varied or, in case of a simultaneous operation, a rope and cable mess has to be expected. This means that the steering ropes and cables entangle and there eventually occurs separate guiding of the individual profiles of the sail. Even if no entanglement occurs, each individual control line has to be individually again attached. In addition, the control ropes have to be handled such that the rear parts or afterleeches of a forward individual profile have to be passed at the front part of the luffs of the individual profiles disposed behind. Thus these individual profiles have to be passed without being entangled. This means that the rear parts have been guided around the respective warping point in each case.
If this results in delays during actual maneuvering, for example because of the entanglement, then the danger of capsizing is naturally very large. Just because of this problem, but also because of the rope entanglement, this conventional proposal has not had much success. This can be understood since for nearly every individual profile a special operation would be required.